A. Field
The present invention relates to a method for opening a gripper clamp of a gripper of a weaving machine, whereby a clamp stop piece of the gripper clamp engages a stop element which is adjustable by means of a motor drive, and to a device for carrying out said method.
B. Related Art
It is known (WO 97/40218) to adjust—at predetermined positions along the longitudinal excursion path of the gripper—a stop element for the gripper clamp stop piece using a motor drive. Said positions are predetermined by a control unit as a function of weaving parameters, illustratively depending on weaving at nominal or at low speeds. During the normal weaving operation, the stop element is positioned closer to the shed than for slow mode weaving. The higher the weaving rate, the more closely the stop element must be positioned to the shed.
Both the shed's opening/closing and the gripper position outside the shed relative to the angular position of the main drive shaft change substantially as a result of the elastic deformations of the individual components, both during slow mode and normal weaving operations.
When the loom runs at high speed in normal operation and additionally slow operation (crawling mode) for example to allow adjustments, it is possible that the stop element's set excursion in the direction of gripper excursion path sometimes will fall short.
In the slow mode, the opening of the gripper clamp should be carried out as late as possible because then problems will be minimized. Even tardy opening does not entail serious problems, because this only results in an excessively long filling waste part. Because slow mode weaving is carried out only for comparatively few filling insertions, a relatively large filling waste does not represent a serious problem. When rapidly running the weaving machine, however, there is danger that the stop element's set excursion no longer will suffice to implement the latest possible opening of the gripper clamp in slow mode.